Summary
Symantec email blocks can be attributed to various factors including local misconfigurations, relay errors (often indicated by a '553' error due to incorrect SMTP settings or un-whitelisted IP addresses), poor IP reputation, lack of proper email authentication (SPF, DKIM, DMARC), high spam complaint rates, triggering content filters, and improper MX record configurations. Resolving these issues involves verifying SMTP settings, ensuring the sending server is properly authenticated and whitelisted, setting up valid reverse DNS records, implementing SPF, DKIM, and DMARC, improving IP reputation by sending high-quality email and warming up new IPs gradually, setting up feedback loops, regularly cleaning email lists, implementing double opt-in, and reviewing bounce messages or contacting Symantec support for specific details. Proper DMARC policy enforcement is also crucial for handling emails that fail authentication checks.
Key findings
- Misconfiguration & Relay Errors: Local site misconfigurations and unauthorized relay attempts ('553' error) are common causes.
- Authentication Deficiencies: Lack of proper SPF, DKIM, and DMARC authentication is a significant contributor.
- Reputation Problems: Poor IP reputation and high spam complaint rates often lead to blocks.
- MX Record Issues: Incorrect MX record configurations can affect routing and cause deliverability problems.
- List Hygiene Neglect: Sending to inactive or problematic addresses harms deliverability.
Key considerations
- Verify Configurations: Double-check SMTP settings, reverse DNS records, and other server configurations.
- Implement Authentication: Set up SPF, DKIM, and DMARC records to verify email legitimacy.
- Monitor Reputation: Regularly check IP reputation, analyze bounce messages, and engage with feedback loops.
- Practice List Hygiene: Clean email lists regularly to remove inactive or problematic addresses.
- Gradual IP Warmup: Warm up new IP addresses gradually to avoid damaging reputation.
- Symantec Support: If problems persist, engage with Symantec Support for specific issue resolution.
What email marketers say
10 marketer opinions
Symantec email blocks are often caused by local misconfigurations, poor IP reputation, or failing email authentication checks. Solutions include verifying SMTP settings, ensuring valid reverse DNS records, setting up SPF and DKIM records, improving IP reputation by sending high-quality email, warming up new IP addresses gradually, implementing DMARC policies, using feedback loops to address spam complaints, and regularly cleaning email lists.
Key opinions
- Misconfiguration: Local site misconfigurations can cause relay errors, leading to blocks.
- Reverse DNS: A valid reverse DNS (PTR) record is crucial for verifying sending server legitimacy.
- SPF Record: Setting up an SPF record helps prevent spoofing and improves deliverability by specifying authorized mail servers.
- IP Reputation: Poor IP reputation is a common cause; regularly check blacklists and improve sender reputation.
- IP Warmup: Gradually warm up new IP addresses to avoid damaging IP reputation.
- DKIM: Implementing DKIM verifies email authenticity using digital signatures.
- Feedback Loops: Setting up feedback loops helps address spam complaints and improve email programs.
- List Cleaning: Regularly clean email lists to remove inactive or problematic addresses, reducing bounce rates.
- Double Opt-In: Implement a double opt-in process to ensure only legitimate subscribers are added.
Key considerations
- SMTP Settings: Verify SMTP settings to ensure proper authentication and relay permissions.
- Email Quality: Focus on sending consistent, high-quality email to maintain a good sender reputation.
- DMARC Policy: Implement a DMARC policy to provide instructions to receiving mail servers on how to handle emails that fail SPF or DKIM checks.
- Bounce Rate: Monitor bounce rates and spam complaints to identify and address issues promptly.
Marketer view
Marketer from Email Geeks suggests if you're not trying to send email through them then it's a local site misconfiguration.
23 Aug 2023 - Email Geeks
Marketer view
Email marketer from Email Geeks Forum shares that if you're using a new IP address, gradually warm it up by sending email to engaged subscribers first. Avoid sending large volumes of email to unengaged subscribers, as this can damage your IP reputation and lead to blocks.
6 Mar 2023 - Email Geeks Forum
What the experts say
3 expert opinions
Symantec email blocks can stem from a range of issues, including poor IP reputation, inadequate email authentication (SPF, DKIM, DMARC), high spam complaint rates, or triggering content filters. Analyzing bounce messages or seeking assistance from Symantec support can offer specific insights. Maintaining a strong sender reputation involves consistently sending high-quality email, adhering to authentication standards, monitoring bounce and complaint rates, and swiftly addressing any problems. Additionally, understanding MX record priority can help prevent routing issues.
Key opinions
- IP Reputation: Poor IP reputation is a significant cause of Symantec email blocks.
- Email Authentication: Lack of proper email authentication (SPF, DKIM, DMARC) can lead to blocks.
- Sender Reputation: Maintaining a strong sender reputation requires consistent, high-quality email.
- MX Record Priority: MX record configurations can affect routing and potentially trigger blocks.
Key considerations
- Bounce Message Analysis: Reviewing bounce messages can provide detailed reasons for email blocks.
- Symantec Support: Contacting Symantec support can offer tailored troubleshooting assistance.
- Feedback Loops: Engaging with feedback loops provides valuable insights into spam complaints.
- Content Filters: Avoid triggering Symantec's content filters by adhering to email best practices.
Expert view
Expert from Word to the Wise details that improving sender reputation involves sending consistent, high-quality email, adhering to email authentication standards, monitoring bounce rates and spam complaints, and promptly addressing any issues that arise. Engaging with feedback loops can also provide valuable insights.
23 Mar 2025 - Word to the Wise
Expert view
Expert from Word to the Wise explains that Symantec blocks can be caused by various reasons, including poor IP reputation, lack of proper authentication (SPF, DKIM, DMARC), high spam complaint rates, or triggering Symantec's content filters. Reviewing bounce messages or working with Symantec support can provide more specific details.
17 Apr 2023 - Word to the Wise
What the documentation says
4 technical articles
Symantec email blocks are often due to unauthorized relay attempts, which are indicated by a '553' error message. This can result from incorrect SMTP settings or an un-whitelisted IP address. To resolve these issues, ensure the sending server is properly authenticated, the IP is whitelisted, and SMTP settings are correctly configured. Utilize message audit logs for detailed rejection reasons. Implementing a DMARC policy is also crucial to instruct receiving mail servers on handling emails that fail SPF or DKIM checks.
Key findings
- Relay Error: The '553' error indicates an unauthorized relay attempt.
- SMTP Settings: Incorrect SMTP settings can lead to email blocks.
- IP Whitelisting: The sending server's IP address must be whitelisted in the Symantec Messaging Gateway.
- Message Audit Logs: Message audit logs provide detailed reasons for email rejections.
- DMARC Policy: Implementing a DMARC policy is crucial for handling emails that fail authentication checks.
Key considerations
- Authentication: Ensure the sending server is properly authenticated to prevent relay errors.
- Configuration: Correctly configure SMTP settings, including authentication where required.
- Monitoring: Regularly monitor message audit logs to identify and address deliverability issues.
- Policy Enforcement: Enforce DMARC policies to improve email security and deliverability.
Technical article
Documentation from Broadcom Support details that to resolve relay errors, ensure that the sending server is properly authenticated, the sender's IP address is whitelisted in the Symantec Messaging Gateway's relay settings, or the SMTP settings are correctly configured to use authentication if required by the gateway.
21 Dec 2022 - Broadcom Support
Technical article
Documentation from Symantec Support explains that using message audit logs to look at more details of the reason for rejection will help. These often contain a verbose reason for the block.
10 Nov 2022 - Symantec Support
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